Pinched gluon vertex operator in the super world-line formalism Original Research Article

We reformulate, using the super world-line formalism, the pinched gluon vertex operator proposed by Strassler. The pinched vertex operator turns out to be the product of two gluon vertex operators with the insertion of a δ-function which makes the super distances between them zero. Thus the pinch procedures turn out to be nothing but the insertions of δ-functions. Applying our formulation to two-loop diagrams which are the QED correction to gluon scatterings via a single spinor loop, with the QED charge e being replaced by the strong coupling g, we give various formulae on pinched N-point functions.